The water vole is one of Britain’s most endangered mammals. Katie Jarvis went in search of one, but had to settle for an invigorating walk instead

We’re sitting on the sort of little bridge from which Christopher Robin and Winnie-the-Pooh once raced twigs, in the middle of the Sherborne Park Estate. Below us dance the clear waters of the Sherborne Brook, rippling and skipping as they chase towards the River Windrush. In the days when Christopher Robin and friends invented Poohsticks (a gentle sport occasioned by Christopher Robin accidentally dropping a pine cone from a bridge), there would probably have been a whole host of small eyes watching them. Eyes belonging to one of Britain’s most entrancing mammals: the water vole.

So prolific were these aquatic bundles of fur in the early part of the 20th century that Kenneth Grahame made Ratty (an unfair but once-common water-vole appellation) one of the chief adventurers in The Wind in the Willows; so prolific that a nature-book, belonging to my mother as a child, describes them as ‘common objects of the countryside’.

Not so now, sadly.

“Here you go!” says John Field, holding out a handful of olivey-brown ‘Tic Tacs’. “Water-vole droppings.” Over the breeding season – from March to September – these droppings provide a Sherlock-Holmes-type clue to the presence of these shy creatures. “They use latrines to mark their territories,” he explains.

As Gloucestershire Wildlife Trust’s water vole officer, John is an expert. Does he often see them face to face?

“Very rarely, to be honest. They’re beautiful creatures but, unfortunately, it’s one of those things where you might get a chance-sighting, which gives you a nice warm glow. If you want to see them properly, you’ve got to invest a lot of time in sitting, waiting.”

But before you sound any death knell for the water vole, listen up: because there is good news. And it’s happening right here, on this tranquil 4,000-acre estate, where otters frolic and dragonflies proliferate on the 19th century water meadows. As part of the trust’s Cotswold Rivers Living Landscape project, John and his team embarked on a large-scale scheme to enhance wetland habitats – and their work is paying dividends… relatively speaking.

“When you’re surveying for water voles, you don’t come up with a number but an index of abundance,” John says. “What we have here are pockets of low-density animals, so it’s what you call a scarce population. But in a lot of the UK, the water vole is absent. Many areas just don’t have any. They’re still very rare but it’s getting better.”

Water voles are one of Britain’s most endangered mammals, with almost 90% of sites lost in recent years. Nothing is ever simple in wildlife terms but it’s safe to blame two overriding factors for their devastation: an insidious loss of waterside habitat; and, more viciously, the voracious American mink which escaped – and was let loose – from fur farms, and which would eat them for breakfast.

Happily, the national trend for mink is a now downward one. And that’s probably in no small part due to another comeback kid: the otter. “An otter is much bigger than mink, which are intelligent creatures: if there’s a large carnivore on their doorstep, they’ll move away,” John says.

Which, with a bit of luck, leaves the problem of habitat. Make no mistake, that’s no small problem; but here at Sherborne, massive amounts of work are being put into creating the ideal water-vole home. What’s particularly fascinating, strolling round this rolling estate with John, is that the work needed is not always what you might imagine. Take, for example, the weeping bower prettily arching over the brook behind us: willows dabbling their branches onto the bobbing surface and, elsewhere, alders – loved for their catkins – standing sentinel along the bank.

“But look what that over-shading does to the brook,” John points out. On the shadowy side of the bridge, the water is clear and empty, right down to the shallow bed. Yet beneath the surface the other side, which is free from trees, great clumps of carpeting water-crowfoot sway with the current. By selectively pollarding the willows and coppicing alders and other bankside trees, John and team are encouraging healthy bankside and aquatic vegetation, which water voles need both for food and shelter.

Farm animals, too, can cause problems. This land is owned by the National Trust – willing partners in the scheme – which lets much of it out to tenant farmers. The problem is that grazing cattle, looking for a cooling drink, can cause considerable damage to the banks. As a result, the lovely, wide, sweeping bend in the brook just in front of us is not the picturesque feature it appears at first glance.

“What can happen on riverbanks,” John says, “is that the cattle – particularly during low water levels – can chase the water in and destroy banks.”

What the trust has done is to encourage farmers to fence the land off to limit erosion and to install cattle drinking-bays instead. And by building a false bank a few feet into the brook, using bundles of brushwood, John is persuading vegetation to grow back, narrowing the water-course and speeding up the flow. All important when it comes to reducing silts and manure in the brook.

(Interestingly, of course, both these improvements contradict the entrenched layman’s view that all fencing is bad and all trees are good.)

“The work marries in very nicely with other species that utilise the same zone, such as fish, overwintering waders and wildfowl,” John says. “What you do for water vole is what you’d do for others. Not only are you protecting the water quality and all the knock-on effects downstream, but you’re equally preventing the silting up of the gravels, which are important spawning habitat for brown trout.”

As a result, the brook is rich in fish, while swift, kingfisher and birds of prey swoop overhead.

It’s all good news for this furry herbivore that’s closely related to lemmings and muskrats. If you want a few more facts about Britain’s largest vole, here you go: they’re strong swimmers with water-repellent fur but, unlike other semi-aquatic mammals, they don’t have webbed feet and are much more suited to burrowing.

Water voles are also all-too-frequently mistaken for the similarly-sized brown rat, though there are important differences. A water vole’s fur is much silkier and a chestnut – rather than grey – brown. Its ears are smaller and hidden in fur; and, rather than the pointy nose and long scaly tail of a rat, the water vole has a blunt, round snout and a furry tail. Altogether cuter. But mistakes proliferate. (As Emma Bradshaw of the trust relayed to me, they’d quite often be seen in Cirencester by the outdoor-pool users. “They’d come out and climb up the willow, and people walking past would say, ‘Look at the rats!’ We’d say, ‘No! They’re water vole and so rare!’”)

The National Trust, which is delighted to be part of the programme, is also keen to promote public understanding. Later, I speak to Simon Ford, the NT’s South West wildlife and countryside advisor. “We’re clearly very supportive of Gloucestershire Wildlife Trust’s work,” he says. “Seeing these iconic species like the water vole and otter, which are cuddly and wonderful to look at, can often set people off on a track in the future of real interest in wildlife. Then they might become interested in less-cuddly things like rare earwigs – or the Roman snail, which might not look so beautiful but is really interesting and a classic of Gloucestershire.

“There’s occasionally a risk of managing for one species to the detriment of the greater site; but in this case, I don’t see any conflict. I think we can accommodate the water vole and the wading birds and the otters and all those other things and, hopefully, get a cracking site.”

Has Simon seen any water vole at Sherborne? “I have!” he says. “Walking along the little mown path alongside one of the ditches, the very first thing I heard was that ‘plop’, followed by a little nose that disappeared into the long grass. I didn’t see it for very long, but it really lifts the heart.”

He’s one up on me today. But it doesn’t matter – there’s plenty to take in as we stroll through this lovely estate to the historic water meadows, once so vital to local farmers. When the system was introduced several hundred years ago by diverting water from the Windrush, it was an ideal way of protecting and extending the growing season: in spring, the ground would be free from frost; and in dry summers, the land would stay damp. Moreover, the river would provide free fertiliser in the form of deposited silts.

Nowadays, you just can’t get the staff. “Of course, in the old days, you’d have a ‘drowner’ – a skilled worker – constantly monitoring the water levels and operating the sluices,” John says. “We don’t have that luxury today. But derelict water meadows can be important wetland habitats for wildfowl, waders and, particularly in this case, water vole; but only if they remain partially wet throughout the year. The focus of the project was not an attempt to restore a fully-functioning system but to make better use of the water that we do have.”

Certainly, Sherborne provides a tentative and much-welcome good-news story for water vole. But why did they survive here in the first place, when they’ve vanished from so many other English spots?

“I wouldn’t say survived is the right word. Clinging onto the wreckage may be more appropriate,” John cautions.

“As for the future, I don’t think it’s quite as neat a picture as the otter is back, therefore the mink has gone, therefore water voles are recovering naturally. The numbers are low.

“But they will build up over time because the habitat is increasingly there. They will recolonise.”

It’s work that, with the help of volunteers and other agencies, the trust is aiming to replicate elsewhere in the Cotswolds.

And that work is doing something of which Ratty would wholly approve: giving back to the water vole the only world worth having.

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